The present invention relates generally to medical devices for use in conjunction with a virtual colonoscopy procedure, and more particularly to an apparatus and method for removing material from a colon in conjunction with a virtual colonoscopy procedure.
Colorectal cancer is one of the leading causes of deaths from malignancy in the United States, with only lung cancer causing more deaths annually. Colon cancer can be prevented because it usually begins as a benign polyp that grows slowly for several years before becoming cancerous. If polyps are detected and removed, the risk of developing colon cancer is significantly reduced.
Unfortunately, widespread colorectal screening and preventive efforts are hampered by several practical impediments, including limited resources, methodologic inadequacies, and poor patient acceptance leading to poor compliance. Moreover, some tests, such as the fecal occult blood test (FOBT) fail to detect the majority of cancers and pre-cancerous polyps. Additionally, since a sigmoidoscopy only examines a portion of the colon, it also misses many polyps that occur in the remainder of the colon. The accuracy of other tests, such as the barium enema, vary and are not always reliable.
A technique for detecting colorectal cancer using helical computed tomography (CT) to create computer simulated intraluminal flights through the colon was proposed as a novel approach for detecting colorectal neoplasms by Vining D J, Shifrin R Y, Grishaw E K, Liu K, Gelfand D W, Virtual colonoscopy (Abst), Radiology Scientific Prgm 1994; 193(P):446. This technique was first described by Vining et al. in an earlier abstract by Vining D J, Gelfand D W, Noninvasive colonoscopy using helical CT scanning, 3D reconstruction, and virtual reality (Abst), SGR Scientific Program, 1994. This technique, referred to as “virtual colonoscopy”, requires a cleansed colon insufflated with air, a helical CT scan of approximately 30 seconds, and specialized three-dimensional (3D) imaging software to extract and display the mucosal surface. The resulting endoluminal images generated by the CT scan are displayed to a medical practitioner for diagnostic purposes.
There have been several advances in virtual colonoscopy that have improved the imaging techniques, making it a more viable and effective screening option. One advantage of using a virtual colonoscopy as a screening process is the elimination of the invasiveness of a traditional colonoscopy. Traditional colonoscopies are preformed using a colonoscope that has a relatively large diameter (i.e., sufficient to form a seal with the anus) that includes, among other instruments, a scope, multiple lumens for introducing gas and/or liquid, and a working channel for introducing a snare or similar device into the colon. With such a device, there is a risk of straightening and/or perforating the colon because of its relative inflexibility and size.
Another advantage of the virtual colonoscopy procedure is the elimination of the preparation process associated with a traditional colonoscopy. The typical preparation process involves the use of strong laxatives to purge any fecal waste from the colon. Such a process is extremely uncomfortable and is often cited as one of the least desirable parts of the whole procedure. Complete purging is not necessary with the virtual colonoscopy procedure. Rather, a fecal contrasting agent is used to facilitate digital subtraction of any residual feces from the virtual image.
In a virtual colonoscopy procedure, if an area is identified that requires closer inspection, the colon may have to be at least partially purged. In the event some residual material is left in the colon, it is desirable to remove that material using devices that have a smaller diameter than existing colonoscopic devices.
During the virtual colonoscopy procedure, the patient lies on the CT scan area. A thin tube (approximately the diameter of a rectal thermometer) is placed in the rectum, through which air is introduced into in the colon. The air is necessary to distend the bowel allowing any polyps to stand out from the normal surface. The patient holds their breath while the machine sweeps over the abdomen. The procedure is repeated with the patient lying on their stomach. The whole procedure takes approximately ten minutes.
In addition to CT scan imaging modalities, magnetic resonance imaging (MRI) can also be used to perform the virtual colonoscopy. When using MRI, only certain tools can be utilized (i.e., tools with only slight ferromagnetic properties).
Even though the virtual colonoscopy is largely non-invasive as a screening process, a need still exists for non-invasive and minimally invasive devices and methods for treating the colon (e.g., removing polyps) in the event the virtual colonoscopy identifies a problem area within the colon.
Some colonoscopy procedures involve insufflating the colon and removing residual material, such as fecal matter, from the colon. When a virtual colonoscopy is performed, the residual material can be identified to help make the extraction procedure easier. As stated above, in a typical colonoscopy, these procedures typically are performed using multiple instruments, such as a colonoscope having an insufflation tool and a working tool. Since the residual material is identified with the virtual colonoscopy, the number of required instruments is reduced; however, there is still a need for further reductions and improvements in instrumentation. Thus, there is a need for a device that provides an improved process for the removal of material from the colon during a colonoscopy procedure being performed in conjunction with a virtual colonoscopy.